erf(3M)                                                   erf(3M)



NAME
     erf, erfc - error function and complementary error function

SYNOPSIS
     #include <math.h>

     double erf(x)
     double x;

     double erfc(x)
     double x;

DESCRIPTION
     The erf function returns the error function of x (the
     precise formula is available in a standard calculus text).

     erfc, which returns 1.0 - erf(x), is provided because of the
     extreme loss of relative accuracy if erf(x) is called for
     large x and the result subtracted from 1.0 (for example, for
     x = 5, 12 places are lost).

SEE ALSO
     exp(3M)
































January 1992                                                    1